In 1979, a new century was dawning on the Islamic calendar. Throughout the umma, the century's approach was greeted with excitement and apprehension, with a wave of events seeming to foretell an imminent Islamic resurgence. In February, the Ayatollah Khomeini had triumphantly returned from exile to Iran, while on 1 April, the Islamic Republic of Iran was officially proclaimed. November yielded further signs of political Islam's ascendancy. On 4 November, Iranian radicals stormed the American embassy in Tehran, precipitating a 444-day long stand-off that would cement a decades-long estrangement between the ayatollahs and Washington. On 20 November, in a provocation timed to coincide with the advent of the new Islamic century, approximately 200 militants briefly seized and held Islam's holiest place, the Grand Mosque of Mecca, using the occasion to denounce the Saudi monarchy for its perceived profligacy and Westernising tendencies. Finally, as the year drew to a close, the Soviet Union's invasion of Afghanistan further inflamed Islamist sentiments.